Internal combustion engine



Sept. 5, 1933.

G. NEGEL INTERNAL COMBUSTION ENGINE Filed July 22, 1930 Patented Septn 5, 1%33 UNITED STATES PATENT oics Centra, Handels- & Industrie A.-G., Chur,

Switzerland, a corporation of Switzerland Application July 22, 1930, Serial No. 469,663, and in Germany .lluly 22, 1929 3 (Claims.

My invention relates to improvements in internal combustion engines, and more particularly in engines of the type in which great power is developed by means of a large number of pistons acting on the same shaft. The object of the improvements is to provide an engine of this type in which a large number of cylinders and pistons cooperate with a shaft having a small number of cranks, and in which the length of it the engine axially of the said shaft is small. With this object in view my invention consists in combining a plurality of sets of cylinders having a common combustion chamber and disposed radially thereof around the engine shaft, the

' l5 pistons of the inwardly directed cylinders being directly connected to the said shaft, while the pistons of the outwardly directed cylinders are connected therewith through the intermediary of suitable transmission gearings. Each set of 0 cylinders havinga common combustion chamber provides an engine of comparatively high power and efiiciency, and by combining the said sets of cylinders into an engine of high power and having a common engine shaft, the individual cylinders may be made so small that they can be operated without cooling the pistons. the engine can be manufactured at low cost, and it is reliable in operation.

For the purpose of explaining the invention an 39 example embodying the same has been shown in the accompanying drawing, in which the same letters of reference have been used in all the views to indicate corresponding parts. In said drawing,

Fig. 1 is a sectional elevation showing the engine, and

Figs. 2 and 3 are sectional plan views on an enlarged scale taken respectively on the lines 2-2 and 33 of Fig. 1. a

In the example shown in the drawing the engine comprises a casing having end walls 9 and 9 and a circumferential wall 9 In the example shown in the figures the engine comprises six setsl to 6 of radially disposed cylinders a, b, c, and accordingly the circumferential wall 9 is hexagonal in cross-section. The said wall 9 is formed at its corners with six inwardly .di-. rected pockets b which are open at their inner and outer ends, and which have the inwardly directed cylinders a of the sets of cylinders mounted therein. Within the cylinders a, b, c pistons a b and c are mounted, which have a common combustion chamber e. In bearings f 65 of the casing g a crank shaft d is mounted.

Thereby The outwardly directed cylinders b and c are fixed in position by lids 2' and It.

The connecting rods m of the inner pistons a are connected to a crank 11 of the crank shaft d, and the pistons b and c of the outwardly directed cylinders h and c of adjacent sets are connected by their connecting rods in respectively with cranks o of the crank shafts p rotatably mounted in extensions of the walls g and 9 To each of the said crank shafts p a pinion q 65 is fixed which is in mesh with a gear wheel 1', and the said gear wheel 1' is in mesh with a pinion s meshing with a gear wheel t secured to the crank shaft d.

The pistons a b and of each set of cylinders are controlled so that they move in opposite directions, and so that they move simultaneously into the combustion chamber e or out of the samefand for insuring a uniform torque the cycles of the individual sets 1 to 6 are displaced with relation to one another. The relative displacement of the outer six cranks o and the median or main shaft n is such that the pistons a b and c of all the sets have regular movements. As is indicated by the arrows shown in Fig. 1 the rotary movement of the cranks o is transmitted in the reverse direction to the. main shaft d;

The six sets 1 to 6 of cylinders are disposed in one plane, as appears from Figs. 2 and 3, and the power developed by the said sets is transmitted through the transmission gears q, 1', s, t to the main shaft d. Therefore the power developedby the engine composed of six individual engines is high, and its axial length is small, the said axial length corresponding to the breadth of a single set of cylinders. Further, considering the high power developed by the engine its construction is simple, because only seven cranks, viz six cranks oand the median crank n, are needed, which result is obtained by transmitting the movement of the cranks o in reverse direction to the shaft d. The operation of the pistons of each set of cylinders and the sets of cylinders is 1 regular, if the pistons b and c of adjacent sets are connected with a common crank o.

The efllciency of each set oLcylinders is high because the pistons a b and 0 thereof have a common combustion chamber e, which is par- 105 .ticularly advantageous in case of Diesel engines.

By subdividing the power of the engine and developing the same-in a set of individual engines having a good thermic efliciency the thermic strain on the cylinders is reduced so far that cooling of the pistons may be dispensed with." Further, the torque of the engine is uniform.

The engine may be operated on the four-stroke cycle, but I prefer to operate the same on the two-stroke cycle, because the steering mechanism is more simple in construction. As shown in Fig. 1, the inwardly disposed cylinder of each set is provided with exhaust ports y which communicate with suitable exhaust passages. The two outwardly directed cylinders of each set include intake ports 2 for the combustion and scavenging air; the intake ports 2 are visible in Fig. 1 only in the lower set of cylinders and are invisible in the other sets simply because of the positions of the pistons therein.

In the drawing I have shown an engine in which two engines each comprising several sets of cylinders are combined in the same casing g for increasing the power, the said engines being located axially one beside the other. The inner pistons a of both engines are connected with the same crank shaft (1, and the outer pistons b and c act on cranks o of the common crank shaft p. The gear wheels q, r, s and t transmitting the power from the outer crank shafts p to the main crank shaft d may be common to both engines. By disposing several engines axially one beside the other, the number of the cranks of.

the shafts p and d is increased. But in view of the high power of the whole engine its construction is simple and compact.

From the foreging description of the invention it will be understood that high power is developed by means of a large number of cylinders of small diameter. Therefore cooling of the pistons may be dispensed with, because the heat to be transmitted from the pistons is small. Further, a large number of pistons is connected with the crank shaft, and yet the number of the cranks of said crank shaft and the axial length of the engine are small. The engine may be manufactured at low cost, and it is reliable in operation.

In the main engine each set of cylinders arranged in the form of a star is an engine capable of developing high power, and the said engine has a high efficiency because a plurality of cylinders have a combustion chamber in common.

In the embodiment illustrated, I have combined the cranks of the pistons of adjacent cylinders, and placed the sets of cylinders in a common plane. Therefore the pistons of adjacent cylinders of adjacent sets are connected with a common crank. The rotation of the said cranks is transmitted to the main crank in reverse direction, because for obtaining a uniform torque the cycles of the sets of cylinders must be displaced with full relation to each other.

The engine is particularly useful in air craft.

I claim:

1. An internal combustion engine, comprising a central crank shaft, a plurality of sets of cylinders each set having a common combustion chamber and comprising at least three cylinders extending radially from said combustion cham her, said sets being disposed around said crank shaft, pistons in said cylinders. means directly connecting the pistons of the inwardly directed cylinders with said main crank shaft, and gearing connecting the pistons of the outwardly directed cylinders with said crank shaft.

2. An internal combustion engine as claimed in claim 1 wherein the gearing connecting the pistons of the outwardly directed cylinders to the central crank shaft includes auxiliary crank shafts, and means for transmitting rotation therefrom in reverse direction to the central crank shaft, each of said auxiliary crank shafts being common to two pistons belonging respectively to different sets of cylinders.

3. An internal combustion engine as claimed in claim 1, wherein the sets of cylinders around the central crank shaft are disposed in groups side by side, lengthwise of said shaft.

GUNTHER NEGEL. 

